The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic)
Plate tectonic processes introduce oceanic crust (as eclogite) into the sources of oceanic island basalts (OIB). The fate of this recycled material in the deep mantle is still poorly understood. Here we present a systematic study of Zn isotopes on well-characterized alkaline basalts (<5 Ma) from...
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Online Access: | https://oceanrep.geomar.de/id/eprint/59397/ https://oceanrep.geomar.de/id/eprint/59397/1/Liao%20etal.pdf https://doi.org/10.1016/j.chemgeo.2023.121606 |
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ftoceanrep:oai:oceanrep.geomar.de:59397 2024-02-11T10:06:20+01:00 The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic) Liao, Renqiang Zhu, Hongli Geldmacher, Jörg Li, Congying Liu, He Sun, Weidong 2023-09 text https://oceanrep.geomar.de/id/eprint/59397/ https://oceanrep.geomar.de/id/eprint/59397/1/Liao%20etal.pdf https://doi.org/10.1016/j.chemgeo.2023.121606 en eng Elsevier https://oceanrep.geomar.de/id/eprint/59397/1/Liao%20etal.pdf Liao, R., Zhu, H., Geldmacher, J. , Li, C., Liu, H. and Sun, W. (2023) The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic). Chemical Geology, 635 . Art.Nr. 121606. DOI 10.1016/j.chemgeo.2023.121606 <https://doi.org/10.1016/j.chemgeo.2023.121606>. doi:10.1016/j.chemgeo.2023.121606 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2023 ftoceanrep https://doi.org/10.1016/j.chemgeo.2023.121606 2024-01-15T00:27:49Z Plate tectonic processes introduce oceanic crust (as eclogite) into the sources of oceanic island basalts (OIB). The fate of this recycled material in the deep mantle is still poorly understood. Here we present a systematic study of Zn isotopes on well-characterized alkaline basalts (<5 Ma) from the Madeira Islands in the eastern North Atlantic. Our analyses show that the δ66Zn values of alkaline basalts range from 0.25‰ to 0.34‰, with an average of 0.30 ± 0.05‰ (2SD, N = 15), which is similar to the average of mid-ocean ridge basalts (MORB) (0.28 ± 0.03‰, 2SD), and ∼ 0.14‰ higher than that of the asthenospheric mantle (0.16 ± 0.06‰, 2SD). However, these alkaline basalts have higher Zn/Fe ratios (up to 14.20) than MORB (generally less than 12). Model calculations show that the partial melting of mantle peridotite cannot simultaneously produce the observed MORB-like δ66Zn values and trace element ratios. After excluding the effects of post-eruption alteration, crystal fractionation, and the assimilation of crustal materials during magma upwelling on Zn isotopic compositions of the studied samples, we suggest that the MORB-like δ66Zn values reflect the mixing of peridotite melt and eclogite/pyroxenite-derived melt in the magma source of the Madeira hotspot. This is supported by trace element ratios and radiogenic isotopes, such as high Zn/Fe and Dy/Yb ratios and 206Pb/204Pb values. Our new data provide independent evidence in support of the important role of recycled oceanic crust in the source and generation of alkaline OIBs, and also highlight that such sources are not ubiquitously carbonated. Article in Journal/Newspaper North Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Dy ENVELOPE(11.369,11.369,64.834,64.834) Chemical Geology 635 121606 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
Plate tectonic processes introduce oceanic crust (as eclogite) into the sources of oceanic island basalts (OIB). The fate of this recycled material in the deep mantle is still poorly understood. Here we present a systematic study of Zn isotopes on well-characterized alkaline basalts (<5 Ma) from the Madeira Islands in the eastern North Atlantic. Our analyses show that the δ66Zn values of alkaline basalts range from 0.25‰ to 0.34‰, with an average of 0.30 ± 0.05‰ (2SD, N = 15), which is similar to the average of mid-ocean ridge basalts (MORB) (0.28 ± 0.03‰, 2SD), and ∼ 0.14‰ higher than that of the asthenospheric mantle (0.16 ± 0.06‰, 2SD). However, these alkaline basalts have higher Zn/Fe ratios (up to 14.20) than MORB (generally less than 12). Model calculations show that the partial melting of mantle peridotite cannot simultaneously produce the observed MORB-like δ66Zn values and trace element ratios. After excluding the effects of post-eruption alteration, crystal fractionation, and the assimilation of crustal materials during magma upwelling on Zn isotopic compositions of the studied samples, we suggest that the MORB-like δ66Zn values reflect the mixing of peridotite melt and eclogite/pyroxenite-derived melt in the magma source of the Madeira hotspot. This is supported by trace element ratios and radiogenic isotopes, such as high Zn/Fe and Dy/Yb ratios and 206Pb/204Pb values. Our new data provide independent evidence in support of the important role of recycled oceanic crust in the source and generation of alkaline OIBs, and also highlight that such sources are not ubiquitously carbonated. |
format |
Article in Journal/Newspaper |
author |
Liao, Renqiang Zhu, Hongli Geldmacher, Jörg Li, Congying Liu, He Sun, Weidong |
spellingShingle |
Liao, Renqiang Zhu, Hongli Geldmacher, Jörg Li, Congying Liu, He Sun, Weidong The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic) |
author_facet |
Liao, Renqiang Zhu, Hongli Geldmacher, Jörg Li, Congying Liu, He Sun, Weidong |
author_sort |
Liao, Renqiang |
title |
The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic) |
title_short |
The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic) |
title_full |
The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic) |
title_fullStr |
The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic) |
title_full_unstemmed |
The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic) |
title_sort |
role of recycled oceanic crust in the alkaline basalts: evidence from zn isotopic compositions of alkaline basalts from the madeira hotspot (eastern north atlantic) |
publisher |
Elsevier |
publishDate |
2023 |
url |
https://oceanrep.geomar.de/id/eprint/59397/ https://oceanrep.geomar.de/id/eprint/59397/1/Liao%20etal.pdf https://doi.org/10.1016/j.chemgeo.2023.121606 |
long_lat |
ENVELOPE(11.369,11.369,64.834,64.834) |
geographic |
Dy |
geographic_facet |
Dy |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/59397/1/Liao%20etal.pdf Liao, R., Zhu, H., Geldmacher, J. , Li, C., Liu, H. and Sun, W. (2023) The role of recycled oceanic crust in the alkaline basalts: Evidence from Zn isotopic compositions of alkaline basalts from the Madeira hotspot (eastern North Atlantic). Chemical Geology, 635 . Art.Nr. 121606. DOI 10.1016/j.chemgeo.2023.121606 <https://doi.org/10.1016/j.chemgeo.2023.121606>. doi:10.1016/j.chemgeo.2023.121606 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.chemgeo.2023.121606 |
container_title |
Chemical Geology |
container_volume |
635 |
container_start_page |
121606 |
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1790603970032435200 |